package Traverse.traverse2022;

import java.util.LinkedList;
import java.util.Queue;

import domain.ListNode;
import domain.TreeNode;

/**
 * @author leiwenkang <leiwenkang@kuaishou.com>
 * Created on 2022-06-27
 */
public class LayerOrder {

    public static void main(String[] args) {
        TreeNode node1=new TreeNode(1);
        TreeNode node2=new TreeNode(2);
        TreeNode node3=new TreeNode(3);
        TreeNode node4=new TreeNode(4);
        TreeNode node5=new TreeNode(5);
        TreeNode node6=new TreeNode(6);
        TreeNode node7=new TreeNode(7);
        node1.left=node2;
        node1.right=node3;
        node2.left=node4;
        node2.right=node5;
        node3.left=node6;
        node3.right=node7;
        node4.left=node4.right=null;
        node5.left=node4.right=null;
        node6.left=node4.right=null;
        node7.left=node4.right=null;
        layerOrderTraverse(node1);
    }

    public static void layerOrderTraverse(TreeNode root){
        if (root == null) {
            return;
        }

        Queue<TreeNode> queue = new LinkedList<>();
        queue.add(root);

        while (!queue.isEmpty()) {
            TreeNode node = queue.poll();
            System.out.println(node.val);

            if (node.left != null) {
                queue.add(node.left);
            }

            if (node.right != null) {
                queue.add(node.right);
            }
        }
    }
}
